Shaft seal for a rotating machine

Abstract

A shaft seal for a rotating machine having a rotating shaft includes a support ring, surrounding the shaft, supported by a casing. The support ring includes a plurality of movable ring segments and fixed ring segments adjoining each other in a circumferential direction of the support ring. The movable ring segments are biased away from the shaft by biasing members provided at circumferential ends of the fixed ring segments. Sealing fins and sealing sheets are disposed along the inner periphery of the support ring.

What is claimed is:  
     
         1 . A shaft seal for a rotating machine having a rotating shaft comprising: 
 a casing which surrounds the shaft;    a support ring supported by the casing to surround the shaft, including a plurality of movable ring segments and fixed ring segments adjoining each other in a circumferential direction of the support ring and a biasing member provided at a circumferential end of each fixed ring segment to bias the adjoining movable ring segment away from the shaft;    a plurality of sealing fins spaced from each other in an axial direction of the shaft and installed on an inner surface of the support ring to form a labyrinth seal around the shaft; and    a plurality of sealing sheets disposed between two of the sealing fins with a gap between adjoining sheets in a circumferential direction of the shaft, each sealing sheet having an inner end for forming a seal against the outer surface of the shaft.    
     
     
         2 . A shaft seal for a rotating machine as claimed in  claim 1  including a pair of holders mounted on the support ring on opposite sides of the sealing sheets, and a screw which exerts a force on the holders to resist movement of the holders with respect to the support ring.  
     
     
         3 . A shaft seal for a rotating machine as claimed in  claim 1  including a pair of holders mounted on the support ring on opposite sides of the sealing sheets, and a spring which exerts a force on the holders to resist movement of the holders with respect to the support ring.